Apparatus for directing vehicular traffic flow



TM-9.3 XR 3 s 248., 69 i) April 26, 1966 N. A. BLTON 3,248,690

APPARATUS FOR DIRECTING VEHICULAR TRAFFIC FLOW Filed Feb. lO, 1964 2Sheets-Sheet l April 26, 1966 N. A. BQLTON 3,248,690

APPARATUS FOR DIRECTING VEHICULAR TRAFFIC FLOW 2 Sheets-Sheet 2 FiledFeb. lO. 1964 United States Patent 3,248,690 APPARATUS FOR DERECTENGVEHICULAR TRAFFHC FL'GW Norman A. Bolton, Scottsville, N.Y., assignor toThe General Signal Corporation, Rochester, N.Y., a corporation of NewYork Filed Feb. 10, 1964, Ser. No. 343,796 16 Claims. (Cl. Mtl-31) Thisinvention relates to apparatus for detecting particular kinds ofvehicular traflic movement, and more particularly pertains to apparatusarranged relative to adjacent traffic lanes for detecting vehiculartratlic straddling or crossing the boundary between such adjacent traclanes and directing7 such detected vehicles.

The continually increasing use of freeways having adjacent trafiic lanesfor traffic flow in the same direction `with entering ramps and exitingramps coupled thereto has introduced new conditions of tratlic movementswhich are at times `quite hazardous. In this respect, where an enteringramp and an exiting ramp are quite closely coupled to two adjacent traiclanes of the freeway, a vehicle would have to cross the b-oundarybetween such adjacent traffic lanes in order to go from the enteringramp -to the exiting ramp. Such crossing of the boundary by traticpresents hazardous trac movement conditions with respect to traflicm-ovement in the traiiic lane coupled to the exiting lramp which couldquite easily result in tratlic accidents. Another instance in whichvehicles cross or straddle adjacent traffic lanes is at an intersectionwhere a traic signal is controlled for permitting left turn into theintersection. However, unless one or more vehicles actually want to makesuch a left turn, it is desirable to eliminate such left turnindications from the traic signal cycle in order to provide the mostetlicient movement of tratlc through the intersection.

Generally speaking, it is contemplated by the present invention toprovide apparatus for directing the movement of detected vehicular tratcon freeways in order to minimize hazardous conditions which couldotherwise arise. More specically, it is proposed to so arrange vehicledetection apparatus at a critical point relative to adjacent trafficlane-s to detect each vehicle attempting to move from one traffic laneto the other traffic lane. The detection of each vehicle in such vehicledetection zone eifects control of a sign or signal for the purpose ofdirecting the movement of that detected vehicle to a particular one ofthe tratiic lanes.

It is contemplated in the present invention to employ as the vehicledetection apparatus an ultrasonic detection system for detecting trafficstraddling or crossing adjacent traic lanes. In brief, an ultrasonicdetection system employs sound energy having a frequency in theultrasonic range such as, for example, eighteen KC per second which istransmitted by a transmitting transducer in the form of either acombined, steady-energy beam or intermittent bursts of energy, forexample, toward a receiving transducer contiguous to the boundary of theadjacent traffic lanes. It is proposed in the present invention toposition the transmitting transducer above adjacent traffic lanes so asto direct the energy toward a portion of the adjacent trailc lanes fromwhich it is reflected toward the receiving transducer. The ultrasonicdetection apparatusacts in response to such reflected energy to providea normal non-detection indication, but upon interception of suchultrasonic energy by a vehicle such ultrasonic detection apparatus actsto control a traic directing sign or signal as, for example, theillumination of such sign or signal to suitably direct the movements ofthat detected vehicle.

3,248,699 Patented Apr. 26, 1966 By employing ultrasonic detectionapparatus to dene the vehicle detection zone, several advantagesimmediately accrue. One such advantage is that the transmitting andreceiving transducers are located above the traflic lanes and spacedfrom the actual vehicle detection zone so as to provide access ofvehicles of all sizesand shapes to the vehicle detection zone whether ornot they are actually permitted therein. Another advantage is that thepositioning of the transmitting and receiving transducers with respectto a predeterm-ined reflecting portion of the adjacent traffic lanes isquite variable so that the present system can accommodate any number ofdiiferent applications where it is desired to provide a vehicledetection z-one relative to adjacent traic lanes. In this respect, theenergy transmitted from the transmitting transducer strikes therellecting portion of the adjacent tratlic lanes at an angle ofincidence depending upon the position of suc-h transmitting transducerwith such energy being reilected from such reflecting portion at anangle of retlecti-on correspond-ing to the angle of incidence. As longas the receiving transducer is positioned in alignment with the energyreflected at its angle of reection, proper operation of the system canbe had.

One of the advantages inherent in the illumination of a sign or signalfor directing vehicular traffic movement is that the motorists attentionis quickly directed to that sign or signal. In response to the sign orsignal indication which arrests the motorists attention, a generallymore 4favorable reaction by the motorist results such that possiblehazardous conditions ot traiiic movement is minimized.

It is thus one object of this invention to provide detection apparatuspositioned t-o define a vehicle detection zone relative to the boundaryof adjacent trac lanes for directing the movements of all vehicular tracentering such detection zone.

Another object of this invention is to provide detection apparatushaving a transmitting transducer and a receiving Itransducer rwhich `arevariably positionable with respect to a predetermined portion ofadjacent traine lanes at their boundary to dene a detection zone havingan area sufcient for detecting all vehicles entering that predeterminedportion of adjacent traflic lanes.

Another object of this invention is to provide vehicle detectionapparatus positioned -for detecting all vehicular traffic entering apredetermined portion of adjacent traffic lanes at their boundary foraltering the operation of other existing trafc direction signalsadjacent thereto.

Othesr objects, purposes and characteristic features of the presentinvent-ion will in part be disclosed in the drawings, and in part bepointed out as the description of the invention progresses.

In describing the invention in detail, reference will be made to theaccompanying drawings in which: FIG. 1 is a diagrammatic viewillustrating the vehicle detection apparatus of the present inventionpositioned for dening a vehicle detection zone on a freeway;

FIG. 2 diagrammatically illustrates a side view of the relativepositioning of the transmitting and receiving transducers with apredetermined portion of the adjacent traffic lanes on such freeway fordening the vehicle detection zone;

FIG. 3 illustrates in block diagram form one embodiment of vehicledetection apparatus for controlling a tratlic directing sign; and

FIG. 4 diagrammatically illustrates a typical two phase intersectionwith which the vehicle detection apparatus of the present invention isemployed to control a traic signal to permit detected vehicles to turnleft.

Referring now toFIG. 1, a FREEWAY having two trafc lanes 7 and 8 forvehicular tratiic in the same direc'- 3 tion is illustrated. An ENTERINGRAMP permits movement of vehicles into traic lane 7 of the FREEWAY asindicated by arrows 9, while an EXITING RAMP permits the movement ofvehicles from traliic lane 8 of the FREEWAY as indicated `by arrows 10.In addition, arrows 9 and l@ indicate that traffic may ow on respectivetraic lanes 7 and 8 beyond the EXITING RAMP. Where the ENTERING RAMP andEXITING RAMP are located in near proximity, it is often desired to limittratiic movement on the ENTERING RAMP and EXIT- ING RAMP to the trafficlane of the FREEWAY to which it is coupled in order to avoid congestionof vehicular traic upon the FREEWAY. In this connection, trafc lane 7 onthe FREEWAY may have one or more NO LEFT TURN indications printed theronprior to reaching the area of the EXITING RAMP as shown in FIG. l.

Lying between traiiic lane 7 and traic lane 8 near the EXITING RAMP, aHORIZONTAL DET ECTION ZONE is shown in dotted outline which is definedby ultrasonic detection apparatus. More specically, ultrasonic energy asreferred to above is transmitted in a beam from transmitting transducerT toward a portion of adjacent tratic lanes 7 and 8 which portion isindicated to be a REFLECTING SURFACE from which such ultrasonic energyis reected toward a receiving transducer R. The width of such ultrasonicbeam generally constitutes the width of the HORIZONTAL DETECTION ZONE.The transmitting transducer T is held in an overhead position by a mastor arm 16, while the receiving transducer R is held in an overheadposition by a mast or arm 17. The transmitting transducer T andreceiving or transducer R are electrically coupled as suggestedrespectively by dotted lines 19 and 20 to ultrasonic detection apparatus21. Ultrasonic detection apparatus 21 comprises electronic circuits forgenerating the ultrasonic energy at the frequency of, for example,eighteen kc. per second and for acting on such ultrasonic energy whenreceived, or in the absence of such ultrasonic energy, to control a NOLEFT TURN sign 22 as suggested by dotted lines 23.

Turning now to FIG. 2, a side view showing the relative positioning of atransmitting transducer T and a receiving transducer R relative to theREFLECTING SURFACE is illustrated. Transmitting transducer T ispositioned above the FREEWAY a distance D1 which may -be in the orderof, for example, twenty feet. In addition, transmitting transducer T isspaced from the REFLECTING SURFACE a distance D2. As positioned,transmitting transducer T transmits ultrasonic energy toward theREFLECTING SURFACE of adjacent traic lanes 7 and 8 so as to cause suchenergy to strike such reflecting surface at a predetermined angle ofincidence i. Such ultrasonic energy is then reected from. such reectingsurface at an angle of reilection r which corresponds to the angle ofincidence z'. According to the angle of incidence z' and angle ofreflection 1' employed, a predetermined VERTICAL DETECTION ZONE isformed in which all entering vehicles intercept the ultrasonic beam ofenergy. The receiving transducer R is positioned in alignment with thereected ultrasonic energy so that such eneregy may be received by thereceiving transducer R in the absence of a vehicle in the vehicleDETECTION ZONE. Receiving transducer R is positioned above the FREEWAY adistance D3 and spaced from the REFLECTING SURFACE a distance D4.

-Itis contemplated that the distance D1 and D2 for transmittingtransducer T are variable according to the particular area of detectionrequired for a given application. For any given set of distances D1 andD2, however, the angle of incidence z' and angle of reection r will besimilar for the selected set of distances. The receiving transducer Rm-ay then be positioned in alignment with the reectcd ultrasonic energyso as to have its distances D3 and D4 either shorter, the same as, orgreater than distances D1 and D2, respectively.

Turning now to FIG. 3, the apparatus of the present invention is shownin block form for controlling the NO LEFT TURN sign 22 according to thenon-detection or detection of vehicles in the vehicle DETECTION ZONE. Itis here suggested that the ultrasonic detection apparatus isconventional as shown in the prior art. A vehicle relay VR is controlledby ultrasonic detection apparatus 21 according to the non-detection ordetection of a vehicle in the vehicle DETECTION ZONE. Duringnondetection periods, vehicle relay VR is maintained picked up. However,during the detection of a vehicle, vehicle relay VR is dropped away.

For each vehicle detection which causes relay VR to be dropped away, theNO LEFT TURN sign 22 is controlled. In this connection, delay circuit 24receives control energy through back contact 26 of relay VR during theperiod that such relay VR is dropped away. Delay circuit 24 is providedfor controlling the NO LEFT TURN signal 22 as soon as it is activatedupon detection of a vehicle and for Ia short predetermined intervalafter such vehicle is no longer detected in order to control the NO LEFTTURN sign 22 for a suiiicient duration such that it remains illuminatedfor a suicient time period to alert the motorist of that detectedvehicle. Delay circuit 24 maybe, for example, a conventional one-shotmultivibrator.

Turning now to FIG. 4, a two-phase intersection is illustrated whichincludes a LEFT TURN ONLY traiiic lane having a traic signal S1associated therewith as well as two additional traic lanes each having atraic signal associated therewith, these trathc signals being designatedS2 and S3. Local controller apparatus 40 is provided in u block form forcontrolling traffic -signals S1, S2 and S3 in any Well known manner. Inaddition, traic signal lights 32, 33 and 34 are illustrated in .blockform for the other directions of tratiic movement at such intersectionand are indi-cated to be controlled by the local controller apparatus 30as suggested by dotted line 35.

In the diagrammatic example of FIG. 4, the vehicle detection -apparatusof the present invention is employed in conjunction with localcontroller apparatus 30 in order to operate trafiic signal S1 to displaya green arrow only ifa vehicle is detected as entering the LEFT TURNONLY traflic lane. More specifically, transmitting transducer T andreceiving transducer R `are illustrated as being positioned relative tothe REFLECTING SURFACE lying between the LEFT TURN ONLY traffic lane andthe adjacent trac -lane 36. Transmitting transducer T and receivingtransducer R are spaced from such REFLECT- ING SURFACE and elevated inposition above the traffic lanes similar to that shown in FIG. 2 fordirecting a beam of ultrasonic energy tow-ard the REFLECTING SUR- FACEfrom which it is reflected toward receiving transducer R to define avehicle DETECTION ZONE as shown in FIGS. l and 2.

Transmitting transducer T and receiving transducer R are electricallycoupled to ultrasonic detection apparatus 21 as suggested by dottedlines 19 and 20 respectively for operating relay VR in the mannerdescribed above for FIG. 3. Oper-ation of relay VR controls a memorydevice 42 through its contact 26. More specically, Venergy iselectrically coupled through back contact 26 of relay VR duringdetection of a vehicle in the vehicle DE- TECTION ZONE to operate memorydevice 42 to its abnormal condition of operation. In its abnormalcondition of operation, memory device 42 controls local controllerapparatus 30 as suggested by line 43 for the purpose of modifying itscycle operation to the extent that signal S1 is controlled to display agreen arrow indication to traffic in the LEFT TURN ONLY lane forpermitting the detected vehicle to rnove through the intersection. Inorder that memory device 42 be reset to its normal condition ofoperation, it is suggested that local controller apparatus 30 beeffective at or near the end of its cycle during which it controlssignal S1 to display a green arrow indication to control memory device42 as -suggested by line 44.

The feature of resetting the memory device 42 by the local controllerapparatus 30 at or ne-ar the end of its cycle permits the memory device42 to be operated to its abnormal condition of operation by a Vehicledetected after the cycle of the local controller apparatus 30 iscompleted. Upon return of operation of local controller apparatus 30during its next cycle to that part of such cycle in which signal S1 maybe controlled to display its green arrow indication, local controllerapparatus 30 is again controlled by memory device 42 for controllingsignal S1. Although it is suggested herein to employ only a singletransmitting transducer T and a single receiving transducer R fordefining the vertical ldetection zone, it is contemplated that aplurality of transmitting transducers T and a plurality' of receivingtransducers R could be employed where a substantially longer vehicleDETECTION ZONE is desired. For example, a plurality of pairs oftransmitting transducers T and receiving transducers R may be employedwith each such pair tuned to a different frequency and so mounted inIposition above adjacent traffic lanes las to cause the transmittedenergy of different irequencies to be reflected from predeterminedreiiecting surfaces to the correspondingly tuned receiving transducers.

Having shown and described apparatus for directing vehicular trafficflow a-s one embodiment of the present invention, it is to be understoodthat this embodiment has been selected to facilitate in the disclosureof t-he invention rather than to limit the number of forms which it mayassume; and it is to -be further understood that various modifications,adaptations and alterations may be applied to the specific embodimentshown to meet the requirements of practice without in any mannerdeparting from the spirit or scope of the present invention.

1. A system for detecting vehicles straddling the boundary between twoadjacent traffic lanes comprising, in combination,

(a) first nonobstructing means for transmitting a predetermined signalcontiguous to said boundary a pre-determined distance substantially inalignment with the flow of vehicular traffic in said two adjacenttraffic lanes,

(b) vsecond nonobstructing means for receiving said predetermined signaluntil `a vehicle straddles said boundary within said predetermineddistance and intercepts said predetermined signal,

(c) means responsive to said second nonobstructing means for each periodduring which said signal is absent therefrom for indicating detection ofthe vehicle intercepting said predetermined signal.

2. A -system for detecting Vehicles straddling the boundary between twoadjacent trafic lanes' comprising, in combination,

(a) first means located in relation to said boundary nonobstructive totraffic flow for transmitting a predetermined signal contiguous to saidboundary in alignment with the ow of vehicular traflic in said twoadjacent traffic lanes,

(b) second means located in relation to said boundary nonobstructive totr-afiic flow and opposite to said first means for receiving saidpredetermined signal continuously except for the period each vehiclecrosses said boundary and intercepts said predetermined signal,

(c) -means responsive to said second means for each said period forindicating detection of the vehicle intercepting lsaid predeterminedsignal.

3. The system according to claim 2 in which said first means includesdirecting means for directing said signal contiguous to said boundary ina narrow beam, whereby each of the vehicles travelling in said twotraffic lanes intercepts such signal only when it straddles saidboundary.

4. The system according to claim 3 wherein said first means and saidsecond means comprise an ultrasonic detection system in which saidpredetermined signal is u-ltrasonic energy generated by said first meansand directed in the narrow beam by said directing means and received bysaid second means unless intercepted by a vehicle straddling saidboundary.

5. The system according to claim 4 in which said ultrasonic energy asgenerated is a continuous signal.

6. The system according to claim 4 in which said ultrasonic energy asgenerated is intermittent in the form of ultrasonic energy bursts.

7. A system for detecting vehicles crossing the boundary between twoadjacent traiiic lanes comprising, in combination,

(a) first means aligned with said boundary for directing a signaltransmitted thereby toward said boundary from which said signal isreflected unless intercepted by a vehicle,

(b) second means aligned with said boundary and on the side of thereflecting portion of said boundary opposite to said first means forreceiving such re- -flected signa-l,

(c) means responsive to said second means during each interval thereofin which said signal is absent for indicating detection of the vehiclecrossing said boundary and intercepting said signal.

8. The system according to claim 7 in which said first means includes atransmitting element suspended above said boundary a distance greaterthan the highest vehicle travelling on said two adjacent traic lanes fordirecting said signal toward said boundary, said second means having areceiving element suspended above said boundary a distance also greaterthan the highest vehicle travelling on said two adjacent traffic lanesand on the side of said reecting portion opposite to said transmittingelement, whereby any vehicle may pass beneath said transmitting elementor said receiving element along said boundary.

9. The system according to claim 8 in which the distance of saidtransmitting element above said boundary is equal to the distance ofsaid receiving element above said boundary and the longitudinaldistances of said transmitting element and receiving element from thereflecting portion are equal.

10. The system according to claim 8 in which the distance of saidtransmitting element above said boundary and its longitudinal distancefrom said boundary are unequal respectively with the distance of saidreceiving element above said boundary and its longitudinal distance fromsaid boundary, said receiving element being disposed in the path of saidsignal as reflected from said portion of itll boundary unless suchsignal is intercepted by a ve- 11. A system for detecting vehicles-straddling the boundary between two adjacent traffic lanes comprising,in combination,

(a) first means positioned above said boundary for directing atransmitted signal toward a particular portion of said two adjacenttraffice lanes including the boundary therebetween from which saidsignal is reflected,

(b) second means positioned above said boundary and from the side ofsaid portion opposite to said first means for receiving saidtransmitting signal reected from said portion except for the period eachvehicle straddles said boundary including said portion and interceptssaid signal, and

(c) means responsive to said second means for each such period forindicating detection of the vehicle intercepting said signal.

12. A system for detecting vehicles crossing the boundary between twoadjacent traflic lanes and directing the movements thereof comprising,in combination,

(a) first nonobstructing means for transmitting a predetermined signa-.lcontiguous to said boundary sub- Stantially in alignment with the flowof vehicular traiic in said two adjacent trailic lanes,

(b) second nonobstructing means flor receiving said predetermined signaluntil a vehicle crosses said boundary and thereby intercepts saidpredetermined signal, and

(c) traihc direction means positioned relative to at least one of saidtwo trafc lanes and responsive to said second means for each periodduring which said signal is absent therefrom for providing an indicationto direct the movement of the detected vehicle.

13, The system according to claim 12 wherein said first nonobstructingmeans and said second nonobstructing means comprise an ultrasonicdetection system in which said signal is ultrasonic energy generated bysaid rst nonobstructing means and directed in a beam contiguous to saidboundary generally toward said second nonobstructing means until saidsignal is intercepted by a vehicle, at least one of said two traicelanes having a traic lane coupled thereto, said traffic direction meansincluding a sign effective to display a distinctive indication when saidtrafc direction means is controlled to direct the movement of thedetected vehicle away from such coupled traffic lane, said sign beingresponsive to said second nonobstructing means for each interval thatsaid signal is intercepted by a vehicle. v

14. The system according to claim 13 in which said second nonobstructingmeans includes delay means responsive during each interval that saidsignal is intercepted by a vehicle for controlling said sign for apredetermined interval after the detected vehicle no longer interceptssaid signal.

15, The system according to claim 12 wherein said rst nonobstructingmeans and said second nonobstructing means comprise an ultrasonicdetection system in which said signal is ultrasonic energy generated bysaid first nonobstructing means and directed in a beam contiguous tosaid boundary generally toward said second nonobstructing means untilsaid signal is intercepted by a vehicle, said two tratlic -lanes beingincluded in an intersection of traic lanes having at least two othertraic lanes for oppositely owing traic transverse thereof, said traicdirection means including traffic directing signals and means forcontrolling said signals through predetermined cycles or" operation,said means being responsive to Said second nonobstructing means at leastduring the interval a vehicle intercepts said signal to control one ofsaid trac directing signals to a proceed aspect for a predeterminedinterval for directing the detected vehicle to turn onto one of said twoother trafc lanes.

16. The system according to claim 1S in which said second nonobstructingmeans includes a memory means controlled to a storage conditionresponsive to said second nonobstructing means upon interruption of saidsignal by a vehicle for controlling said means causing it to effectcontrol of said one traic directing signal, said means being effectiveat substantially the termination of said predetermined interval tocontrol said memory means to a non-storage condition.

No references cited.

NEIL C. READ, Primary Examiner.

THOMAS B. HABECKER, Examiner.

1. A SYSTEM FOR DETECTING VEHICLES STRADDLING THE BOUNDARY BETWEEN TWOADJACENT TRAFFIC LANES COMPRISING, IN COMBINATION, (A) FIRSTNONOBSTRUCTING MEANS FOR TRANSMITTING A PREDETERMINED SIGNAL CONTIGUOUSTO SAID BOUNDARY A PRE-DETERMINED DISTANCE SUBSTANTIALLY IN ALIGNMENTWITH THE FLOW OF VEHICULAR TRAFFIC IN SAID TWO ADJACENT TRAFFIC LANES,(B) SECOND NONOBSTRUCTING MEANS FOR RECEIVING SAID PREDETERMINED SIGNALUNTIL A VEHICLE STRADDLES SAID BOUNDARY WITHIN SAID PREDETERMINEDDISTANCE AND INTERCEPTS SAID PREDETERMINED SIGNAL, (C) MEANS RESPONSIVETO SAID SECOND NONOBSTRUCTING MEANS FOR EACH PERIOD DURING WHICH SAIDSIGNAL IS ABSENT THEREFROM FOR INDICATING DETECTION OF THE VEHICLEINTERCEPTING SAID PREDETERMINED SIGNAL.